A 20-year-old woman suffering mild hypothermia was rescued from the Rideau River near the Cummings Bridge on Tuesday night.

Paramedics said the woman had been in the water on her own initiative for more than an hour.

Firefighters brought the woman out of the shallow water to paramedics.

She was in serious condition.

Paramedics used what were described as "passive re-warming techniques" to bring up her body temperature safely, then took her to hospital where she was listed in stable condition.

Police are investigating.